Uniflow, double-opposed piston type two-cycle internal combustion engine

Abstract

In a uniflow, double-opposed piston type two-cycle internal combustion engine of the type having first and second crank chambers attached to the ends of a cylinder, first and second pistons disposed in the first and second crank chambers, respectively, and slidably fitted into the cylinder so as to move toward and away from each other, an exhaust port formed through the cylinder wall and opened and closed by the first piston, and a plurality of scavenging ports formed through the cylinder wall and opened and closed by the second piston, an improvement comprising means for feeding the rich air-fuel mixture to some of the scavenging ports, means for feeding the lean air-fuel mixture or the air to the remaining scavenging ports, and the lean mixture or air scavenging ports being uncovered and opened earlier than the rich mixture scavenging ports, whereby the scavenging efficiency may be improved and the amount of air-fuel mixture escaping through the exhaust port together with the combustion products may be minimized. In addition, the first piston is advanced in phase by a predetermined degree over the second piston so that the compression ratio may be increased and consequently the engine output may be increased.